Electrical and Electronic Properties in Conducting-Insulating Polymers Composites and Its Applications

本研究以尺寸和形状可控的导电聚合物包覆绝缘聚合物为导体，以未包覆的绝缘聚合物球为绝缘体，制备了一种新型的导体-绝缘体复合材料。详细研究了渗流阈值附近涂覆绝缘聚合物浓度对电导率的影响。当导电聚合物涂覆绝缘聚合物的浓度超过2-5vol%时，电导率提高了15个数量级以上，相当于有效的聚吡咯浓度为0.01-0.03vol%。渗流阈值取决于绝缘聚合物的涂层纤维的形状，但不取决于涂层绝缘聚合物的类型。渗流阈值随涂覆聚吡咯绝缘纤维长度的减小而增大。还研究了临界指数与外加电压的关系。临界指数随外加电压的增加而增大，这可以用渗流模型中的粒间隧道传导来解释。在介电常数与复合材料中导电聚合物浓度的关系中也观察到了渗流阈值。提出了导电-绝缘聚合物复合材料的应用前景。

In this study, a new type of conductor-insulator composites are prepared in which conducting polymer coated insulating polymers, whose size and shape are well controlled, are used as conductor and noncoated insulating polymer spheres are used as insulator. The dependence of electrical conductivity on concentration of coated insulating polymers near a percolation threshold is studied in detail. The conductivity is enhanced by more than 15 orders of magnitude when the concentration of conducting polymer-coated insulating polymer exceeding 2-5 vol%, which corresponds to an effective polypyrrole concentration of 0.01-0.03 vol%. The percolation threshold depends on the shape of the coated fiber of the insulating polymer but does not depend on the type of coated insulating polymer. The percolation threshold increases with decreasing length of polypyrrole-coated insulating fibers. The dependence of critical exponent on applied voltage is also studied. The critical exponent increase with increasing applied voltage, which can be explained by taking account of interparticle tunneling conduction in percolation model. The percolation threshold is also observed in the dependence of dielectric constant on the concentration of conducting polymer in the composite. The applications of conducting-insulating polymer composite have also been proposed.